The primary goal of the Histology core will be to make available to the investigators of individual projects all available expertise, facilities, techniques and technical support required for morphologic and immunolocalization studies of cultured cells and animal and human tissues at both the light and electron microscopic level. A major aim will be to provide formal descriptive analyses of the heterogeneity of endothelial cells within defined vasculatures at arterial, venous and microvascular levels.